This document provides guidelines for the design, use and maintenance of hardened protective shelters (hereafter referred to as shelters ). It specifies guidance on the layout, structures, equipment and actions related to a shelter. This document is intended for organizations or individuals responsible for or involved in decision-making, planning, implementation, administration, use or upkeep of shelters, such as local, regional and national governments, civil protection agencies, first responders and businesses such as designers, constructers and equipment suppliers. This document does not cover the minimum requirements or exact specifications for the properties of or actions related to a shelter; nor does it cover rapidly erected temporary shelters, such as lightweight canvas weather shelters, other tarp tent shelters, or metal and container shelters. Military shelters are subject to additional requirements which are outside the scope of this document.